Wide beam angle LED assembly

ABSTRACT

A LED assembly includes a baseplate and a diffuser. A circuit board connected to the baseplate has a first set of LEDs directed to emit light toward the diffuser. Additionally, a frame is attached to the baseplate and positioned to surround the circuit board. A flexible circuit with a second set of LEDs is attached to the frame, with the LEDs positioned to emit light predominantly perpendicular with respect to the first set of LEDs.

CLAIM OF PRIORITY

This application is a continuation of U.S. patent application Ser. No.16/996,300, filed Aug. 18, 2020, which claims the benefit of priority toU.S. Provisional Application Ser. No. 62/890,850, filed Aug. 23, 2019,and claims the benefit of priority to U.S. Provisional Application Ser.No. 62/952,932, filed Dec. 23, 2019, each of which is incorporatedherein in its entirety by reference.

TECHNICAL FIELD

The present disclosure relates generally to a ceiling or generalillumination light emitting diode (LED) light assembly with a wide beamradiation pattern.

BACKGROUND

Ceiling mounted incandescent bulb illumination systems traditionally hadseveral advantages. Incandescent bulbs were inexpensive to control andmount and can easily provide a wide radiation pattern. Additionally,produced light can have a desired color, assuming proper selection ofbulbs having a desired color temperature.

General illumination LED lighting systems can also be mounted onceilings or walls of buildings and are widely used in locations formerlysupporting incandescent bulbs. Unfortunately, without expensiveintegrated optics, such lighting systems typically present a Lambertianradiation pattern, with most light captured within 160° angle.Unfortunately, this eliminates almost all light when viewed from theside. In the ceiling light application, it is a desirable to have aswide a radiation pattern as possible, sufficient to mimic that of anincandescent bulb.

In addition to problems associated with providing wide beam angles,being able to uniformly provide light of one or more colors can bedifficult. LED systems typically support multiple LEDs of differingcolors that require careful positioning to ensure far field colormixing. Since LEDs of various color can be distributed over a largearea, effective far field color mixing can be difficult.

SUMMARY

In one embodiment, an LED assembly includes a baseplate and a diffuser.A circuit board connected to the baseplate has a first set of LEDsdirected to emit light toward the diffuser. Additionally, a frame isattached to the baseplate and positioned to surround the circuit board.A flexible circuit with a second set of LEDs is attached to the frame,with the LEDs positioned to emit light predominantly perpendicular withrespect to the first set of LEDs.

In one embodiment, the circuit board is positioned in a center of thebaseplate.

In one embodiment, the diffuser, circuit board, and baseplate arecircular.

In one embodiment, the first and second set of LEDs are connected toeach other in parallel.

In one embodiment, the first and second set of LEDs have the same numberof LEDs.

In one embodiment, color of the first and second set of LEDs isadjustable.

In one embodiment, ends of the flexible circuit are attached to eachother.

In one embodiment, ends of the flexible circuit further comprise solderpads.

In one embodiment, ends of the flexible circuit further comprise tabsextending from the flexible circuit and including solder pads.

In one embodiment, the first and second set of LEDs are connected to apower and control module.

In another embodiment, a lighting system includes a power and controlmodule and a circuit board with a first set of LEDs directed to emitlight in a first direction. A frame is positioned to surround thecircuit board and a flexible circuit with a second set of LEDs ispositioned to emit light at a second direction distinct with respect tothe first set of LEDs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B respectively illustrate in top and cross sectional viewan example of a light suitable for ceiling attachment and havingimproved light uniformity;

FIG. 2 illustrates a ceiling light with and without a circular flexcircuit;

FIGS. 3 and 4 illustrate alternative ways for attaching ends of acircular flex circuit together; and

FIG. 5 illustrates a power and LED control unit.

DETAILED DESCRIPTION

FIGS. 1A and 1B respectively illustrate top and cross sectional views ofan example of a lighting system 100 suitable for ceiling attachment andhaving improved light intensity and color uniformity. The lightingsystem 100 includes a baseplate 110 able to support various componentsof the system. The baseplate 110 is typically coated or formed from ahighly reflective or white surface to redirect any, incident light outof the system 100 (away from the baseplate 110), The baseplate 110 isco-extensively covered by a translucent diffuser 112 that assists insmoothing out light beam intensity and helping merge any separate colorbeams, Only attached edges of the diffuser 112 are illustrated in FIG.1A in order to better see the overall system 100.

The baseplate 110 has an attached circuit board 120 that supports anumber of LEDs 122. The circuit board 120 is typically a circular orrectangular printed circuit board able to support LEDs 122, variouselectronic components, and connecting power and control electricaltraces.

The LEDs 122 can be individually set, grouped, or set into an array. TheLEDs 122 can emit light of a single color or can further includemultiple colors. As illustrated, four groupings of LEDs 122 are shown,for a total of twelve (12) serially connectable LEDs. In operation, thelight of LEDs 122 is predominantly emitted away from the circuit board120 (towards the diffuser 112).

Surrounding circuit board 120 and attached to the baseplate 110 is aframe 130 that supports a flex circuit 132 having LEDs 134. The flexcircuit 132 can be laminated onto the frame 130 for mechanical supportand cooling. In one embodiment, the frame 130 can be a circular metalframe cut from a stainless steel or aluminum cylinder, Other shapes arealso possible, including rectangular, ovoid, or other shapes similar tothat of diffuser 112. In some embodiments, a solid frame is notrequired, with separated studs or attachments points being used to holdthe flex circuit. Typically, height of the frame 130 is at least as wideas the flex circuit 132. The frame 130 can also be used to elevate theflex circuit 132 to a suitable height that is determined by the opticaldesign. The frame 130 can have mechanical features that allow quick andeasy rigid attachment to the baseplate 110, including but not limited tospring latches, clips, or screw threaded attachment points.

The flex circuit 132 can include one or more flexible strips thatsupport LEDs 134, electrical traces, passive electronic components, suchas resistors, transistors, or capacitors, and active electroniccomponents such as LED driver components. In the illustrated embodiment,the flex circuit 132 is dimensioned to form a circular strip, withopposing ends of the strip being optionally mechanically andelectrically connected. Typically, the flex circuit 132 is shaped to besimilar to frame 130, so it is be flexible enough to form rectangular,ovoid, or other shapes similar to that of diffuser 112. In operation,light from the LEDs 134 of the flex circuit 132 is predominantly emittedperpendicular (i.e. sideways) with respect to the LEDs mounted on thecircuit board 120.

Both the flex circuit 132 and circuit board 120 can be serially, inparallel, or separately connected to a power and LED control unit 140.The control unit 140 can control light intensity or color. For example,the control unit 140 can manage correlated color temperature (CCT)tuning over a wide range, with a user being able to change the tint ofwhite light along an industry standard operation (iso)-CCT line desired.One example of a suitable control unit 140 and lighting system isprovided by Lumileds proprietary Fusion system, with allows wide tuningcolor range on a single platform.

In one embodiment, a number of series connected LEDs supported by thecircuit board 120 is selected to be matched by the number of seriesconnected LEDs 134 supported by the flex circuit 132. Since the numberof LEDs are the same, and electrical characteristics of the LEDs can beselected to be similar or identical, the LED string forward voltages ofthe LEDs 134, 122 matched. Advantageously, this can ensure that the flexcircuit 132 and the circuit board 120 can be connected in parallelwithout further measures.

FIG. 2 illustrates a ceiling light 200 without a circular flex circuitinstalled. As seen, the ceiling light 200 provides nonuniform light,with a visually significant bright spot 202 being evident. When acircular flex circuit is installed as seen with respect to ceiling light200′, the bright spot is significantly reduced.

FIGS. 3 and 4 illustrate alternative ways for attaching ends of acircular flex circuit strip together (and to the control unit 140). Asseen FIG. 3 , a circular attached flex circuit system 300 includes aflex circuit strip 310 supporting a number LEDs 320. The flex circuitstrip 310 is joined along dotted line 330, with solder pad contacts 340and 342 being, respectively, connected to each other. Similarly, as seenin FIG. 4 , a circular attached flex circuit system 400 includes a flexcircuit strip 410 supporting a number LEDs 420. In contrast to theembodiment of FIG. 3 , the flex circuit strip 410 has flaps or tabs 450that extend away from the strip 410. These tabs 450 can support soldercontacts and can simplify connection to external power or control wires.As shown, the flex circuit strip 410 is joined along dotted line 430,with solder contacts 440 and 442 being connected to each other.

The contacts 340, 342, 440, 442 can be connected to power or othercontrol signals of the control unit 140. The signals of the control unit140 can be connected by a wire, trace, or other conductive member to onethe contacts 340, 342, 440, 442 or other contact.

FIG. 5 illustrates a power and LED control unit 500 suitable forcontrolling a lighting system such as described herein. The control unit140 can include one or more of the components of the control unit 500.As seen in FIG. 5 , the control unit 500 includes a power and controlmodule 510 that includes a connectivity module 512 and connectedmicrocontroller 514. The connectivity module 512 can include wireless orwired connection for user or automatic control via the microcontroller514. In some embodiments, smart phones with lighting apps installed canbe used to provide lighting control and determine lighting status (e.g.,lights on or off). The microcontroller 514 can also control a colortuning module 516 that is able to change or adjust LED color. Controland power is provided to LED device 532 in an LED module 530 via LEDinterface circuitry 520.

The power and LED control unit 500 is similar to that discussed withrespect to FIG. 1 and can include necessary circuitry so as to enablethe operation of the plurality of LEDs. Furthermore, the LED circuitboards of the LED module or LED device 532 can include the necessarycircuitry so as to enable individual or grouped operation of theplurality LEDs in LED device 532. In some embodiments, each LED can beseparately controlled by controller, while in other embodiments groupsof LEDs can be controlled as a block. In still other embodiments, bothsingle LEDs and groups of LEDs can be controlled. In one embodiment,intensity can be separately controlled and adjusted by settingappropriate ramp times and pulse width for each LED using a pulse widthmodulation module control unit 500. This allows staging of LEDactivation to reduce power fluctuations, and to provide superiorluminous intensity control.

The LEDs discussed in this disclosure can include but are not limited toLEDs formed of sapphire or silicon carbide. The LEDs can be formed froman epitaxially grown or deposited semiconductor n-layer, A semiconductorp-layer can then be sequentially grown or deposited on the n-layer,forming an active region at the junction between layers. Semiconductormaterials capable of forming high-brightness light emitting devices caninclude, but are not limited to, Group semiconductors, particularlybinary, ternary, and quaternary alloys of gallium, aluminum, indium, andnitrogen, also referred to as III-nitride materials. In certainembodiment, laser light emitting elements can be used.

Color of emitted light from the LEDs can be modified using a phosphorcontained in glass, or as a pre-formed sintered ceramic phosphor, whichcan include one or more wavelength converting materials able to createwhite light or monochromatic light of other colors. All or only aportion of the light emitted by the LEDs may be converted by thewavelength converting material of the phosphor. Unconverted light may bepart of the final spectrum of light, though it need not be. Examples ofcommon devices include a blue-emitting LED segment combined with ayellow-emitting phosphor, a blue-emitting LED segment combined withgreen- and red-emitting phosphors, a UV-emitting LED segment combinedwith blue- and yellow-emitting phosphors, and a UV-emitting LED segmentcombined with blue-, green-, and red-emitting phosphors.

Direction of light emitted from each LED can be modified by one or moreoptics. Optic can be a single optical element or a multiple opticelements. Optical elements can include converging or diverging lenses,aspherical lens, Fresnel lens, or graded index lens, for example. Otheroptical elements such as mirrors, beam diffusers, filters, masks,apertures, collimators, or light waveguides are also included. Opticscan be positioned at a distance from the LED elements in order toreceive and redirect light from multiple LEDs. Alternatively, optics canbe set adjacent to each LED element to guide, focus, or defocus emittedlight. In some embodiments, optics are connected to actuators formovement. In some embodiments, actuator movement can be programmed. Thisallows, for example, a lens to be moved to increase or decrease beamsize.

Many modifications and other embodiments of the invention will come tothe mind of one skilled in the art having the benefit of the teachingspresented in the foregoing descriptions and the associated drawings.Therefore, it is understood that the invention is not to be limited tothe specific embodiments disclosed, and that modifications andembodiments are intended to be included within the scope of the appendedclaims. It is also understood that other embodiments of this inventionmay be practiced in the absence of an element/step not specificallydisclosed herein.

The invention claimed is:
 1. A light emitting diode (LED) assembly,comprising: a baseplate, a diffuser situated over the baseplate; acircuit board connected to the baseplate and having a first set of LEDsdirected to emit light toward the diffuser; a hollow, integrally formedframe attached about a center of the baseplate and positioned tosurround the circuit board and extend beyond a top-most extent of thefirst set of LEDs; a flexible circuit strip with a second set of LEDsattached thereto, the flexible circuit strip attached to the frame so asto surround the circuit board, with the second set of LEDs positioned toemit light predominantly perpendicular with respect to the first set ofLEDs, the second set of LEDs situated to emit light away from thecenter.
 2. The LED assembly of claim 1, wherein the circuit board ispositioned in the center of the baseplate.
 3. The LED assembly of claim1, wherein the diffuser, circuit board, and baseplate are circular. 4.The LED assembly of claim 1, wherein the first and second set of LEDsare connected to each other in parallel.
 5. The LED assembly of claim 1,wherein the first and second set of LEDs have the same number of LEDs.6. The LED assembly of claim 1, wherein color of the first and secondset of LEDs is adjustable.
 7. The LED assembly of claim 2, wherein endsof the flexible circuit strip are attached to each other.
 8. The LEDassembly of claim 7, wherein ends of the flexible circuit strip furthercomprise solder pads.
 9. The LED assembly of claim 8, wherein ends ofthe flexible circuit strip further comprise tabs extending perpendicularfrom a longitudinal axis of the flexible circuit strip and include (i)solder pads coupled to each other and (ii) further solder pads coupledto a power and control module.
 10. The LED assembly of claim 9, whereinthe first and second set of LEDs are connected to a power and controlmodule, the power and control module situated on an opposing side of thebaseplate as the circuit board, first set of LEDs, the frame, and secondset of LEDs.
 11. A lighting system, comprising: a power and controlmodule; a circuit board with a first set of light emitting diodes (LEDs)directed to emit light in a first direction; a hollow, integrally formedframe attached about a center of the baseplate and positioned tosurround the circuit board and extend beyond a top-most extent of thefirst set of LEDs; a flexible circuit strip with a second set of LEDsattached thereto, attached to the frame so as to surround the circuitboard, with the second set of LEDs positioned to emit light at a seconddirection distinct with respect to the first set of LEDs, the second setof LEDs situated to emit light away from the center.
 12. The lightingsystem of claim 10, wherein the first direction is substantiallyperpendicular with respect to the second direction.
 13. The lightingsystem of claim 10, wherein the frame and the circuit board are attachedto a baseplate.
 14. The lighting system of claim 10, wherein the firstand second set of LEDs are connected to each other in parallel.
 15. Thelighting system of claim 10, wherein the first and second set of LEDshave the same number of LEDs.
 16. The lighting system of claim 10,wherein color of the first and second set of LEDs is adjustable.
 17. Thelighting system of claim 10, wherein ends of the flexible circuit stripare attached to each other.
 18. The lighting system of claim 10, whereinends of the flexible circuit strip further comprise solder pads.
 19. Thelighting system of claim 18, wherein ends of the flexible circuit stripfurther comprise tabs extending perpendicular from a longitudinal axisof the flexible circuit strip and include (i) solder pads coupled toeach other and (ii) further solder pads coupled to a power and controlmodule.
 20. The lighting system of claim 13, wherein the power andcontrol module further comprises a connectivity module and a colortuning module, the power and control module situated on an opposing sideof the baseplate as the circuit board, first set of LEDs, the frame, andsecond set of LEDs.